FIELD OF THE INVENTION
The field of the present invention is air bag systems of a type having an air bag which can be expanded and spread from an upper surface of an instrument panel into a compartment to hold an occupant of a seat and particularly, lid structures of a system for covering an opening in the upper surface of the instrument panel through which the air bag is spreads.
DESCRIPTION OF THE PRIOR ART
There is a conventionally known air bag system in which when a deceleration equal to or more than a given value is sensed upon colliding of a vehicle, an air bag expands and spreads into a compartment by pressure produced by an inflator, thereby holding and protecting an occupant of a seat to protect from a shock due to a secondary collision.
For an occupant of an assistant driver's seat, one such air system is Generally mounted within an instrument panel. Such air bag systems are classified into two types: a high mount type in which an air bag spreads into a compartment through an opening in a front face of the instrument panel and low mount type in which an air bag spreads into a compartment through an opening in a lower portion of the instrument panel.
Recently, air bag systems of a so-called top dash mount type have been proposed in which an air bag spreads into a compartment through an opening formed in an upper surface of an instrument panel. In this type, it is possible to more reliably protect the head of an occupant from collision against a front windowshield or the instrument panel.
In general, the air bag system of the top dash mount type comprises a lid mounted on an upper portion the instrument panel to extend in a widthwise direction of a vehicle. The lid is urged outwardly and opened by pressure generated by the air bag being expanded within the instrument panel. During this time, the lid is pivotally moved or turned about lid-turning center line defined at a front edge side of the lid to a position in which a free end of the lid at its rear edge side abuts against an inner surface of the front windshield or windshield of a vehicle.
In the lid structure of the above prior art air bag system, however, for example, the following disadvantage encountered: because the lid-turning center line is defined in the widthwise direction of the vehicle, the free end the lid, when it is opened, does not equally abut against the inner surface of the front windowshield which is relative to a line extending in the widthwise direction the vehicle, which may result in a localized load being applied to the lid to cause a deformation of the lid.